This invention relates to semiconductor devices encapsulated in plastic material and more particularly to improved integrated circuit power devices such as integrated circuits of the linear type for television purposes in which substantial amounts of internally generated heat must be dissipated during the circuit operation.
Because the active device commonly called the chip or die of a semiconductor integrated circuit devices is very small, the removal from the chip of heat generated during operation thereof has consistently been an important consideration in the overall device construction. Previously a high heat conductivity ceramic or a metal encapsulating medium having high heat conductivity capabilities were generally utilized for devices of so high a power.
With plastic encapsulation the dissipation of heat through the plastic packaging medium is relatively poor because of the relatively low thermal conductivity properties of the plastic. To remove the heat produced during operation of the device metal tabs that protrude from one end of the plastic packaging have been provided for coupling to a larger heat sink. Generally a large metal tab is utilized because the flow of heat from the die or chip is then directed through a substantial length of reduced cross section having poor heat transfer characteristics. Accordingly the size of the package has been substantially increased to compensate for the size of the heat sink.